2Pack Enhanced 4S 40A 16.8V Li-ion Lithium Battery Protection Board PCB BMS Charger Protection Circuit Balance Charging Module for Drill Motor Motorcycle Battery (4S 40A)

Works well, used 4 x 18650 li-ion cells together for a drill. The two boards were connected together on arrival but easily split apart by bending slightly. Installed in my drill and charged up to full power. Tested the drill, it works fine, have not used it for any projects yet though. Will update review if have any problems.

Needs better instruction on how to connect it up. Made mistakes and blew two boards. Seems to work okay when connected properly.

Exceptional value and service. Thank you

Not working as advertised. I purchased the board to protect my 4s battery pack from overdischarge, but it did not cut the power and let it drain down to 12.5v. I am glad i caught it in time, and shut it down. However, a discharge below 2.8v may damage the cells. The device seems not to be working.

I bought this to prototype a pack, and while it seems to balance my cells, and is easy to use, there no way it can handle 40A as stated. At even short bursts of about 25A some of the components on the board are toast. It’s not exactly a knock against the board, it works fine at lower currents. Just know that you’re probably safe in the 5 amp range.